jack_control needs to be run with python2: fps@cherry ~/src/guix$ jack_control ep File "/home/fps/.guix-profile/bin/jack_control", line 80 print 'shit' [sic] The interpreter shebang points to a python3.4 though #!/gnu/store/l9vhjpqza8piap4r047m5xfz86wnxgqw-python-wrapper-3.4.3/bin/python name_base = 'org.jackaudio' control_interface_name = name_base + '.JackControl' Flo